In recent years, with the spread of personal computers and digital cameras, image processing has come to be performed widely. Where image processing is applied to an original image using an image processing application software, which is also called a photo retouch software, it is necessary to determine the values of parameters such as filter application range and intensity and the extent of color tone adjustment.
Determining these sorts of parameter values is difficult for a beginner, and therefore applications that have the ability to set the best parameter values automatically are also available. However, with such automatic setting it is difficult to obtain the best value for each and every image, and normally most such applications determine the final parameter values through some sort of trial-and-error process.
In order to facilitate this sort of adjustment of parameter values based on trial and error, an application having a so-called preview function that enables a plurality of processed images to be displayed in such a way that the images can be compared is known.
By contrast, image processing apparatuses equipped with simple image processing capabilities are available as well. Specifically, functions are known that perform such effects when sensing images as intensifying colors so as to create more vivid color images, or, conversely, creating plain images, or again making the entire screen monochromatic or sepia-tinted.
In addition, it is desirable to have a configuration that enables the display not only of a preview screen but also of the original image after displaying the preview screen, in order to permit the effects of the image processing to be checked and to allow the image processing to be reset if necessary. Although such a configuration is of course necessary in such cases as, for example, conversion of the original images into a sepia-tinted image or a monochrome image, or where image processing is applied to the image screen as a whole such as in edge emphasis, it is even more necessary in the case of image processing that is applied to only a portion of an image.
For example, when applying such image processing as converting a specific color in the original image (for example, red) to another color (for example, yellow) the preview image changes the red area in the original image to yellow. In such a case, without being able to compare the preview image with the original image it is difficult for the user to check the effect of the image processing, and the user can find it difficult to change the source color (in this case red) or the destination color (yellow) because the original colors are lost.